I did a little research this weekend at the Dayton library. I found Henry I. Fourman in the book "Families of Darke County" I also found him in the census from 1850, and I drove out to the Ithaca cemetary and found his tombstone. He was definitly Leah's father, and her mother was Catharine Rider and they both came from PA. I did run into a couple problems. According to the Bio. of Henry he had a son named Jacob in 1837. I am not sure, however, that the jacob in the bio was actually his son. In the census it does show a Jacob with his family but the age is very clearly marked as 74. I looked at a photocopy and it's not even close to looking like a 1. Also the census specifically records that Jacob had no occupation, a little unusual for 14 year olds. Although many had jobs, if they didn't normally it wasn't recorded. His place of Birth is given as Ohio, but I don't know if that is any more reliable than the date, obviously he was not born in OH in 1776.
I could not find the names of Henry or Catharine's parents or the location they came from in PA. I am wondering if a large group of Foremans came to Darke co., together around 1832-33. I was not able to find the census index or abstracts for Darke Co., 1840, which might clear up Jacob.